Jean-Eric Vergne insisted he wasn't going to worry about making comparisons with the rest of the field after making his maiden appearance in an official F1 practice session.

The Renault World Series runner-up replaced Jaime Alguersuari in the Toro Rosso line-up for the first session of the weekend in Korea but faced tricky conditions as rain fell.

As a result, the Frenchman managed just nine laps over the course of the 90 minutes and was 13th quickest in the session.

Although the quicker second session saw him slip down the timesheets, Vergne said he was pleased to have been able to hit the track at the Yeongam circuit even it he couldn't really compare his performance to anyone else.

"Free practice one was the first time I have driven this car," he said. "The last time I drove a Toro Rosso was last year at the Young Driver Test in Abu Dhabi.

"I admit that I was not so happy when I opened the curtains this morning and saw the rain. I found this morning session quite difficult because of the very wet track conditions, although I am happy with what I have done, because I didn't crash the car and I had some fun as well. It is difficult to judge how I did, because normally in a session like this, you get two runs with time in between to look at the data and see how to improve, but the weather meant that was not possible this morning. I had nothing to compare myself with and I definitely am not comparing my performance to any other drivers today.

"It was just a case of getting some experience and learning a bit more about how the team operates. Whatever the track conditions, I am pleased to have been given the opportunity, even if I did not get many laps completed. It means I will now be better prepared when I get back in the car for FP1 at Abu Dhabi."